Antenna accessory



Oct. 6, 1953 J. FINKEL 2,654,857

ANTENNA ACCESSORY Filed Oct. 27, 1949 INVENTOR. '5 4O (JUL us ;NKL

Patented Oct. 6, 1953 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to antenna accessories for high frequency receiver antenna installations such as are employed for television and frequency modulation home sets.

More particularly, the invention pertains to lightning arresters for such sets.

It is an object of the invention to provide an accessory of the character described which constitutes relatively few and simple parts, is comparatively inexpensive to manufacture and can be easily and rapidly attached.

It is another object of the invention to provide an accessory of the character described which is efiicient, reliable, and durable.

Other objects of the invention will in part be obvious and in part will be pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements and arrangements of parts, which will be exemplified in the device hereinafter described and'of which the scope of application will be indicated in the appended claims.

In the accompanying drawings in which is shown-one of the various possible embodiments of the invention,

Fig. 1 is a front view of a lightning arrester constructed in accordance with the invention;

' Figs. 2 and 3 are side and back views, respectively, thereof;

Figs. 4 and 5 are sectional views taken substantially along the lines 4-4 and 5-5, respectively, of Fig. l;

Fig. 6 is an enlarged fragmentary sectional view taken substantially along the line 66 of Fi 1;

Fig. 7 is a perspective view of a saw-tooth washer which is one of the elements of the lightning arrester; and

Fig. 8 is a back view of the lightning arrester as it appears before the same is sealed.

Referring now in detail to the drawings, the reference numeral I0 denotes a lightning arrester constructed in accordance with my invention and designed to be used on conjunction with a'transmission lead-in line I2 of the conventional parallel conductor type, commonly known as a twin lead transmission line. Such a line consists of two wire conductors I 4, [6 which usually are stranded, being spaced apart a predetermined distance and fixedly held in such position by embedding in the opposite longitudinal edges of a ribbon 18 of synthetic plasti The lightning arrester includes a body or housing 20 made from a hard electrically non-conthe washer against the wire ductive material such as a phenolic resin or a ceramic, for example, porcelain. The housing may be of elongated rectangular configuration and its front face is grooved longitudinally to provide a shallow wireway 22 of the proper width to freely receive a standard 300 ohm twin lead transmission line extending longitudinally thereof and lying flat against the bottom of the wireway.

Means is included to aid in confining the line in the wireway, such means as herein shown comprising a pair of overhanging ledges 24 in one piece with the housing 29 and projecting a short distance over the wireway. One of the ledges is disposed adjacent one end of the wireway and the other adjacent the other end, the ledges running along substantial portions of the wireway and each ledge overhanging a diiferent edge thereof.

Near each end of the body, at the edge of the wireway opposite that overhung by the nearby ledge 24, there is provided means to physically engage the adjacent edge of the twin lead transmission line and to electrically engage the ad jacent conductor wire. Each such means comprises an electrically conductive saw-tooth washer 26 fabricated, for example, from brass. This washer constitutes an annular flat disk 28 having an upstanding rim 33 which is serrated to provide a circular set of closely spaced, slender, sharply pointed teeth 32. The washer is mounted on an electrically conductive terminal post 34 spaced from the wireway a distance less than the radius of the washer whereby the circle of teeth will cross over the adjacent conductor of the twin lead transmission line. Said post is received in an opening 3% running from the front to the back of the housing, the headed rear end of the post being seated against a single-lug washer 38 which rests against the rear surface of the housing. The post is held in place by a nut 40 screwed on its threaded forward end. In order to force I employ a cap nut 42 which also is screwed on the forward end of the post. When said nut presses against the annular disk of the washer, it will cause the teeth thereof to penetrate the plastic insulation of the transmission line and engage a stranded conductor. To permit proper movement of the washer the front surface of the housing beneath the washer is at about the level of the base of the wireway or lower.

The back of the housing is deeply recessed to form a cavity 44 in which the heads of the terminal posts 3 4 are located.

The housing is provided with another frontto-back opening 46 which may be centrally disposed and which receives an electrically conductive grounding post it whose head is in a countersunk recess 50 at the front of the housing in the center of the wireway. A nut 52 is threaded on the grounding post and serves to hold the same in place and to retain a double-lug washer 54 against the bottom of the cavity 44.

The lightning arrester further includes a pair of current blocking means such as negative-flow discharge tubes 54 each of which comprises a hermetically sealed glass envelope 56 filled with an inert gas, such as neon, under a pressure of 10 mm. of mercury. If desired, argon also may be included. A pair of lead wires 58 sealed in the envelope support nickel electrodes .69 whose surfaces are activated with alkaline earth oxides. The surfaces of the electrodes and the spacing therebetween are so selected that the breakedown. voltage for glow discharge is in the order of 90 volts D. vC. This voltage should not exceed 50;) and preferably is approximately 100 volts. A practical minimum break-down volta e is '70 vol s.

At the voltage prevailing in the transmission line during operation of a receiver, there is only a negligible flow of current between the elec trodes so that for normal operation the lightning arrester does not cause any noticeable loss of signal strength. It may be mentioned that at r 6 volts D. C., the tubes have a resistance of 75,000 ohms. However, because of their relatively low break-down voltage, the tubes are able to bleed ofi high voltage transients before they have reached a magnitude suificiently large to injure the receiver.

one terminal of each tube 54' is connected to a lug Washer 38 at a terminal post 34. Both other lead wires are connected to the lug washer 55 at the grounding post 48. In this fashion provision is made to lead all high voltage transients to ground.

The cavity 414 is partly filled with a mass of pitch or any other suitable electrically non-conductive mastic which will act as a waterproofing 1 seal 56 and protection forthe internal wiring, round n p t. r a os and tub s. after the same have been installed.

The roundin post 48 is sufficiently i s o permit its tip to project through the waterproof seal .5 as best sh wn. in g- Received on id nroie t n t p. is a grounding strap 58 n is in of a len th of p fo ed le t cally conducti e material. Sa d s rap, for example m e f hricated from alumin m r zinc-c at d sheet steel and is form d with a ongitudinal s ries f 1 forations 56 through one of which the t p h groundin po t extends. The s ap includes. a pair of integral pr jecting fin ers 62 lo ated n opposite sides of the aperture throu h which the grounding post extends. Said fingers are dise posed alongside projections 54, molded in one piece with the housing 2!! and extending into the cavity A l. T st ap s b to form a fiat 6'6 coplanar with the fingers 52 and from which two reaches, 68, Hi extend. Opposite edges of the flat 66 are disposed alongside difierent edges of the projections (54 other than those alongside of whiGh the fingers 6.2 are located. This arrangement prevents, the strap from turning about the grounding post. Said strap is held against the seal by a nut 1.2 and lock washer 14.

The strap 53 is designed to be connected to. a

V grounded element.

suitable means is included to facilitate the mounting of the housing. As shown herein, said means constitutes a pair of front-to-back bores 16 which are designed to receive screws or bolts (not shown).

It thus will be seen that there is provided a device which achieves all the objects of the invention and is well adapted to meet the conditions of practical use.

As various possible embodiments might be made in the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter herein decribed, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

Having thus described the invention, there is claimed as new and desired to be secured by Letters Patent:

1. A lightning arrester for a twin lead transmission line constituting a ribbon of flexible electrically non conductive material having conductors embedded in its Opposite longitudinal edges, said arrester comprising a body of hard electrically non-conductive material adapted to be mount ed on a supporting surface and having a wireway groove extending across a face thereof remote from said supporting surface, said groove being dimensioned to receive said line lying flat therein, said body having two non-overlapping overhanging ledges formed in one piece therewith, one ledge being on one side and at one end of said groove and the other ledge being on the other side and at the other end of said groove and each ledge projecting over said groove, a pair of electrically conductive washers having sawtooth upstanding rims, a pair of electrically con.- ductive terminal posts carried by said body, said terminal posts being adjacent the ends of the wireway groove and on sides thereof opposite from the ledges, said washers being mounted on said posts with the. teeth of the washers facing toward the groove, the axis of each of said, posts being closer to the wireway than the radius of the washers, an element engaging each terminal post and cooperating therewith upon rotation of the element to force the teeth of the washer into an edge of a transmission line disposed within said wireway, an electrically conductive grounding post carried by said body, a pair of negativeglow discharge tubes whose breakdown voltage is between '10 and 500- volts, said tubes being mounted within the interior of the insulating body, and circuit means connecting each tube in series between a different terminal post and the grounding post.

2. A lightning arrester for a twin lead transmission line constituting a ribbon of flexible electrically non-conductive material having conduct tors embedded in its opposite longitudinal edges, said arrester comprising a body of hard electrically non-conductive material adapted to be mounted on a supportingsurface and having a wireway groove extending across a face thereof remote from said supporting surface, said groove being dimensioned to receive said line lying flat, therein, said body having two noneoverlapping, overhanging ledges for-med in one piece therewith, one led e being on. n i e n a on e d. o said groove and the other ledg being on the other side and at the other end of said groove and each ledge -proj ectingover said roove, means to physically engage the upper-marginal edges of the transmission'line adjacent the, ends of the wireway and on sides thereof oppositev from the ledges and to press said line against the bottom 5 of the wireway, each said last-named means including an electrically conductive element arranged to pierce said line, an electrically conductive grounding post, and current blocking means intermediate said post and each element.

JULIUS FINKEL.

Name Date Koch Oct. 15, 1935 Number D. 97,233

Number 6 Name Date Schenck Mar. 26, 1901 Russell Nov. 8, 1904 Shinn Jan. 4, 1910 Everett Dec. 27, 1921 McFarlin Aug. 23, 1932 Cook Nov. 26, 1935 Frank et a1 Nov. 11, 1941 Beckett Apr. 3, 1945 Wallace Nov. 4, 1947 Wilson Mar. 9, 1948 Johnson May 4, 1948 

